In the papermaking field, rotary joints are often used to deliver hot fluid, e.g., hot oil, to a rotating calendar roll to heat the surface of the roll. Bearings, requiring a dedicated lubrication system, are generally used to support and separate the rotating and stationary components of the joint. Mechanical seals are generally used to prevent leakage of the fluid as it passes from a supply, through the rotary joint and into the calendar roll. These bearings and seals are subject to failure, and in some cases failure of the rotary joint may result in fire due to the presence of the hot oil.
Similar joints are used in the textile industry, for example, on laminating rolls used in carpet manufacturing and press rolls in chipboard mills.